Water Gardening, Koi Ponds and a Veggie Filter (Vegetable or
Aquatic Plant Filter)

Water plants in a pond are almost a necessity although of course
koi keepers might just disagree because koi and nothing else are the
focal point in many koi ponds. Koi keepers will never disagree on
the importance of pond plants in any pond situation ... it's just
that they insist upon sparkling, clean and clear fish ponds
disturbed by nothing except those living jewels called koi,
resplendent in their colours shape and movement.

Koi pond enthusiasts often install what they call
a veggie filter outside the main pond. This is often
just a small holding pond through which water flows
before reaching the waterfall. The holding pond or
veggie filter (short for vegetable filter) is packed
with aquatic plants. Water percolating through the
veggie filter becomes lower in nitrate content since
the plants take up the nitrate as nutrients.

The top five (5) plants for vegetable pond filter
are suggested to be as follows ..

The Norfolk Reed
also called by its Latin name, Phragmites
australis. It grows fast which means it uses up
nitrate and phosphate nutrients quickly and
during daylight also produces lots of oxygen so
can be genuinely called an oxygenator aquatic
plant.

Sweet Galingale or
Cyperus longus ... plants like this spread
rapidly and can be controlled by easily cutting
right down to the roots.

Soft Rush or
Juncus effusus

The Bulrush (Scirpus
lacustris)

The Flowering Rush
... Butomus
umbellatus. As the name suggests this does produce a flower.

Veggie filter plants described above would
normally be classed asmarginal aquatics. These grow in bog
type areas naturally or on the
edges of ponds and lakes and slow moving rivers. Most marginal plants are available from tall reeds to low
growing ground cover and are planted using simple pots or specially designed
planting crates (plastic pots but full of
rectangular slotted holes). Just place the planted
aquatics into the pond on ledges or in a specially
prepared holding pond as described for a koi pond
above.

Some people even use box filters and turn these
into veggie or vegetable planting areas. This enable
water to be continuously pumped through the box and
back into the pond.

Water cress has often been used as a suitable
plant for removing nitrates employing the simple
principles of a vegetable filter. Water cress can
become a problem since it is capable of growing
rapidly and "taking over" and once installed can be
difficult to eradicate. Excess nitrates will make it
flourish wonderfully well.